Resisting Ash dieback disease

Ash trees produce high-quality timber, remove carbon dioxide from the air, and provide food and shelter for over 900 wildlife species. They are vital to the ecosystems and economies of the countries they grow in.  

But they are very susceptible to ash dieback, a fungal disease that kills ash trees in Europe’s plantations and woodlands, with grave environmental and economic consequences. In fact, it’s estimated that the disease’s costs to the UK economy alone could come to £7.6 billion by 2029. 

For over 10 years, a research team led by Professor Richard Buggs at Queen Mary University of London has been building a detailed portrait of ash trees’ genes and how they evolve in order to understand how DNA can be used to protect these trees. 

Most recently, in early 2025, the team made an exciting new discovery. They found that natural selection is acting upon the DNA of young ash trees, meaning younger generations of ash trees now have greater resistance to ash dieback than their parents. Their findings offer new hope for the survival of ash trees in the UK and even beyond. 

The research and discoveries of Professor Buggs and his Queen Mary colleagues since 2013 have provided policymakers and forest managers with clear ways to protect and rebuild Europe’s ash woodlands and plantations, including human intervention to accelerate evolutionary change.  

They have shown that selective breeding and prudent felling can manage the disease efficiently, and thanks to their innovative work, Defra now places genomics at the heart of UK forest protection for multiple species beyond ash. 

Over a decade of Queen Mary research  

In 2013, Professor Buggs produced the first draft ash genome with Elizabeth Sollars. This work led to the sequencing of 1,250 UK trees, which, in collaboration with Jonathan Stocks, identified genetic loci associated with ash dieback resistance and subsequently, through a collaboration with Richard Nichols and Carey Metheringham, the development of models to predict resistance to ash dieback. 

In 2018, Professor Buggs carried out a meta-analysis which found mortality rates from ash dieback disease in Europe reached 85% in plantations and 69% in woodlands. 

In June 2025, in collaboration with colleagues from Royal Botanic Gardens, Kew, Professor Buggs and his team’s carried out research which revealed that natural selection was creating a new generation of ash trees, growing naturally in woodland, with greater resistance to the disease.  

Driving progress in UK forest management and policies 

Professor Buggs’ genomics research has revealed that ash trees can evolve to have natural resistance to ash dieback and also shown how to identify resistant trees. These findings were used as evidence for policymakers to determine that selective breeding offers a long-term solution to the ash dieback epidemic. His findings also underpin key sections of Defra’s Ash Tree Research Strategy (2019), which led to the collection of hundreds of more-resistant trees that could be used for breeding.  

In 2022, then Defra minister, Lord Benyon, praised the fast-tracking powers of this new genome-based approach, explaining that we will not need to “wait for five decades [for the species to recover], as we have with elm”. In recognition of this approach, Defra funded similar genomics research at its Centre for Forest Protection to help safeguard more species and appointed Professor Buggs to their Trees and Woodlands Scientific Advisory Group in 2021, on which he provides genomics expertise in relation to numerous species. 

The work of these Queen Mary researchers also indicates that forest managers do not need to pre-emptively fell all their ash trees to prevent the spread of ash dieback and led new guidelines, issued by the Forestry Commission, the Tree Council and Natural England, which advised forest managers to retain healthy trees and promote natural regeneration. This targeted approach to disease management allows more trees to continue providing environmental and economic benefits and avoids costly replanting programmes. 

We’re incredibly proud of the work carried out by Professor Bugg and his team and the huge positive impact it’s having on the UK – and global – ash tree population.